1. Field of the Invention
The present invention relates to a method and an apparatus for detecting non-fermentative bacteria contained in a specimen. Also, the present invention relates to a method and an apparatus for detecting fermentative bacteria and non-fermentative bacteria contained in a specimen. Also, the present invention relates to a method and an apparatus for determining whether the kind of the bacteria contained in a specimen is fermentative bacteria or non-fermentative bacteria. Also, the present invention relates to a method and an apparatus for determining whether the principal bacteria contained in a specimen are fermentative bacteria or non-fermentative bacteria.
2. Description of the Related Art
Bacteria are classified into fermentative bacteria that produce an acidic final product by decomposing sugar and non-fermentative bacteria incapable of decomposing sugar.
As a method for detecting fermentative bacteria, one can mention a Methyl Red reaction test.
When bacteria decompose sugar contained in a medium, an acidic product is produced. In the Methyl Red reaction test, a Methyl Red reagent is used as a pH indicator, whereby the acidification of the medium (i.e. lowering of the pH of the medium) is detected by a change in the color of the added pH indicator. By this change in the color of the medium, one can find whether the sugar in the medium has been decomposed or not, whereby one can detect fermentative bacteria. Generally, in classifying bacteria into fermentative bacteria and non-fermentative bacteria, the Methyl Red reaction test is carried out using a medium that contains purely cultivated bacteria. Then, the bacteria are classified into fermentative bacteria and non-fermentative bacteria on the basis of whether fermentative bacteria have been detected or not.
However, the above-mentioned method requires cultivation for examining whether the bacteria decompose sugar or not, so that it requires about two to three days before fermentative bacteria are detected. Thus, the conventional method requires cultivation work to detect fermentative bacteria. Such cultivation work is cumbersome and requires a long period of time.
As a technique for automatically analyzing bacteria without being accompanied by cultivation of the bacteria, a method disclosed in European Patent Publication No. 1136563 is known. According to this method, by allowing a cationic surfactant to act on a sample containing bacteria, the dye transmittance of the bacteria is promoted. By this, the stainability of the bacteria is enhanced. Then, by performing a fluorescence staining treatment and detecting the fluorescence emitted by the bacteria with a flow cytometer, the bacteria in the sample are detected. With the use of a technique such as described above, one can automatically detect bacteria in a specimen in a comparatively short period of time. However, using such a method, one cannot detect bacteria in a specimen by further classifying the bacteria into fermentative bacteria and non-fermentative bacteria.